This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present invention that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Content, such as multimedia content—e.g. films and music—documents, photos and so on often need to be processed before it is released for the enjoyment of the end user.
Films, for example, pass many processing steps from the actual recording to the release: de-rushing, mixing, addition of digital effects, dubbing, subtitling, and so on.
It will be readily appreciated that a content provider has two requirements for a processing (also called post-processing) system: 1) strict and traceable processing operations, and 2) easy transmission and duplication of the content. The person skilled in the art will appreciate that prior art systems satisfy one or the other requirement, but not both.
Analogue systems generally satisfy the first requirement. As content is stored on tapes or film reels, it is relatively easy to control the processing: a particular content remains with a certain department until the tape is sent to the next department. In addition, it is also possible to trace the tape in case of theft. On the other hand, transmission of the content is less straight-forward, as this requires sending the physical tape, which naturally is difficult, particularly if long distances are involved. It is also difficult to provide the content to more than one entity at once, as the content has to be physically duplicated. In addition, erasing and/or destroying content after use may also provide constraints on the users.
Digital systems provide easy transmission and duplication of content. However, it is much more difficult to control the processing of the content: if the content resides on a server, it is very difficult to control who has access to it and errors may often be made if one department erroneously believes that the previous department has finished processing the content.
FIG. 1 shows an exemplary processing system in which the invention may be used. The system 100 comprises a subtitling device 110, a colour management device 120, a dubbing device 140, a digital special effects device 150, a storage device 160, and an emission clearance device 130, all connected by a network 170.
In the system of FIG. 1, it may for example be required that content pass colour management 120 and digital effects 150 (in no particular order) before being sent to dubbing 140 and optionally further to subtitling 110, before passing through emission clearance 130. As every device has access to the storage 160, it is difficult to control that the workflow is respected.
A solution addressing the security of a workflow management system relies on a Digital Process Management (DPM) system allowing or not the processing of a given content at a given activity of a given content workflow. Prior art uses one of two approaches:                either a pure centralized system which does not allow off-line processing;        or a pure distributed system which causes the issue of impersonating an application, overriding of a work, updating a process definition . . .        
It can thus be appreciated that there is a need for an alternative solution that enables a digital processing system allowing the flexibility of distributed processing scheme while keeping minimal the control in a centralized approach.
The present invention provides such a solution, with a number of variants.